I'm partial to TD Ameritrade and Interactive Brokers, but I'd be interested to hear who everyone else is using.
For the purposes of the poll, I voted for TD Ameritrade because they're who I would use if I could only pick one broker. I actually had an account with Thinkorswim back when they were a broker, and became a TD customer after Thinkorswim was acquired. I've stuck with them over the years for the following reasons:
- They let you trade whatever you want. (futures, equities, options, etc.)
- They offer Thinkorswim, which is a fantastic platform.
- All the FREE data I could ever ask for. Thinkorswim is now integrated with FRED which has been awesome.
- Commissions aren't cheap, but they're reasonable.
- Great customer service.
That said, I'm a big fan of Interactive Brokers and also have an account with them. The reasons I like them are:
- Like TD, they let you trade whatever you want.
- They have very cheap commissions.
- They actually pay reasonable interest on idle cash.
There are some big downsides with IB though. Their platform needs a complete overhaul and they charge for data (which I've never bought).
What I do is use TD and IB in combination with each other. I use TD exclusively for data and analysis, and I use IB to place trades. This way you play to the strengths of both brokers. Note its also good to have multiple accounts in case one broker goes offline and you need to put on a position or hedge real quick.